Wire and insulation attachment for electric terminals



Nov. 17, 1964 J. c. COLLINS 3,157,454

WIRE AND INSULATION ATTACHMENT FOR ELECTRIC TERMINALS Filed May 31, 1962 me l w [i E INVENTOR JOSEPH C. COLL/N5 B & W

United States Patent 3,157,454 WERE ANTI) INdULATTGN '1 F61; ELEQTRTQ TERMTNALS Bioseph C. Qollins, Seituate, 13.1., assignor to North American Philips, New York, N.Y., a corporation of Delaware Filed May 31, 1962, Ser. No. 199,133 2 Clms. (Ch 3392.23)

This invention relates to means for attaching an electric terminal to the end of an insulated wire and it includes structure for obtaining conductive gripping of the bare end of the wire and strain relief gripping of the insulation adjacent to the bare end of the wire.

The present invention comprises a sheet metal structure which is particularly (although not exclusively) adapted to be made in mass production out of a strip of suitable material in unspaced, side-by-side relationship. The terminal has two ends, one of which forms an electrical contact, and the other of which has two sections that grip, respectively, the bare end of an insulated wire to which the terminal is to be connected and the insulation adjacent to the bare end. The section that grips the insulation comprises a pair of insulation-crimping members that are formed out of the sheet metal from which the entire terminal is formed and that originally extend away from the contact end of the terminal. During the manufacture of the terminal the two insulation-crimping members are bent out of the plane of the sheet metal and are twisted approximately 90 degrees in opposite directions. They are also slightly inclined in opposite directions, one being inclined toward the contact end of the terminal and the other being inclined away. These two insulation-crimping members may then be folded over the insulation of a wire adjacent to a short length of bare wire at the very end thereof. The other section of the terminal that grips the bare wire is a pair of tabs that extend out of the plane of the sheet metal in the same direction as the insulation-crimping members. The bare end of the wire falls between these tabs when the wire is inserted into operative relationship with the terminal and the tabs may then be folded over the bare end of the wire in a suitable wire-crimping manner.

The invention will be further described in connection with the drawing in which:

FIG. 1 shows a perspective View of the terminal according to the invention, ready to receive a wire;

FIG. 2 shows the terminal of FIG. 1 crimped onto the end of a wire; and

FIG. 3 shows the terminal of FIG. 1 in an intermediate stage of manufacture.

The terminal in FIG. 1 is a blade suitable for use in a plug of the type commonly associated with lamps and other small electrical appliances. The terminal includes a contact portion 11 in the form of a blade folded back upon itself with one end bent upwardly at an angle of about 90 degrees to form a shelf 12, with the other, longer end extending back away from the contact to a wire and insulation-gripping structure. The section that gips the wire consists of a pair of tabs 13 and 14 that are bent upwardly from opposite edges of the terminal. instead of being at the outermost edges of the terminal these tabs are placed in an indented region for a purpose that will be described in greater detail hereinafter. The tabs 15 and 14 may, if desired, be bent to be approximately 90 degrees to the plane of the sheet metal and substantially parallel to each other. 1

Behind the Wire-crimping tabs 13 and 14 are two insulation crimping members 15 and 1-5. The latter two members are also bent upwardly from the plane of the sheet metal in the same general direction as the tabs 13 and 14, and the angle of bend is preferably approximately degrees. The insulation-crimping members 15 and 16 are also twisted, but in opposite directions, so that the member 15 is tilted slightly away from the contact 11 while the member .16 is tilted in the direction of the contact 11. This places the edges 17 and 18 of the members 15 and 16, respectively, in a preferred relationship to each other to facilitate their being bent over the insulation of a wire when the terminal is attached thereto. Between the insulation-crimping members 15 and 16 may be a small shelf 19. r

In FIG. 2 a wire 21 having insulation 22 thereon has been inserted into the gripping members and has been attached to the terminal. The wire-crimping tabs 13 and 14 have been folded inwardly upon the bare end of the wire 21 to make firm electrical and mechanical connection therewith. Also, the insulation-crimping members 15 and 16 have been folded down across the insulation 22 so that the edges 17 and 18 are substantially, if not exactly, contiguous with each other. This interfitting relationship is facilitated by the opposite inclinations of the members 15 and 16 prior to the time they are folded down upon the insulation.

One of the attractive features of the invention is that it permits very long insulation-crimping members 15 and 16 and yet permits terminals to be made in contiguous relationship to each other on a strip of suitable material such as brass. This is shown in FIG. 3. In FIG. 3 a brass strip having a width W is formed by a punching operation or a series of punching operations together with one or more bending operations so that, when bent along the dotted line 23, the portion 12:: forms the shelf 12 of FIG. 1, and, when bent along the dotted line 24, th portion 111:

forms the shorter end of the contact 11 and the portion 11b forms the other part of the contact 11. Near one edge of this strip semicircular openings 26 and 2.7 are punched out to define the tabs 13 and 14. The latter are cut apart from corresponding tabs of an adjacent terminal along the solid line and are bent up, along the dotted lines 23 and 29, out of the plane of the sheet metal in a later stage of manufacture.

Without the semicircular openings 26 and 27 there would be no material out of which to form the tabs 13 and 14 if the terminals were made in contiguous relationship as shown. Instead it would be necessary to separate adjacent terminals slightly to obtain metal for the tabs 13 and 14, and this would mean that additional metal would be thrown away. Furthermore, the wire is smaller in diameter than the insulation. By selecting the width of the terminals such that the spacing between the insulationcrimping members 15 and 16 is Wide enough to encompass the insulation, tabs 13 and 14 would be spaced too far apart if they were at the outermost edges of the terminal, as the members 15 and 16 are. Instead, by making the semicircular openings 26 and 27, indented regions are automatically formed'so that the root portions of the tabs 13 and 14 are closer together than are the root portions of the. members 15 and 16, thus fitting more precisely around the bare end of the wire.

The insulation-crimping members 15 and 16 initially extend in the opposite direction from the contact 11 and, as may be seen, are formed so that they are slightly inclined toward each other. This permits the diagonal interfitting shown in FIG. 2 when the insulation-crimping members are bent along the dotted lines 31 and 32. The shelf 19 between the members 15 and 16 may be retained to support the back of the insulation when the members 15 and 16 are crimped down, or folded, cross the top of the insulation. As may be seen very little material of the metal strip is thrown away in forming this terminal. While only a portion of an adjacent terminal is shown it is to be understood that any number of successive terminals may be formed in this way.

This invention has been described in terms of a specific embodiment but it Will be understood by those skilled in the art that modification may be made therein without departing from the full scope of the invention as defined by the followingclaims. a

What is claimed is: I

1'. A terminal for attachment to one end of an in sulated wife, said terminal comprising: a sheet metal body portion; a pair of wire-crimping members formed of the sheet metal of said-body portion at opposite sides of a central region thereof and bentintoa generally U-shaped configuration to receive the bare end of said Wire; and a bifurcated end of said body portion, said bifurcated end comprising a pair of insulation-crimping members extending fror'n the outermost side regions of said body portion and formed integrally therewith each said insulation crimping members being bent substantially upright from the plane of said body portion and twisted about their longitudinal axes in opposite directions so that the major surfaces of each said member are substantially parallel to permit the insulation of said wire adjacent to said bare end to be received between said insulation-crimping mem bers. and to permit said insulation-crimping members thereafter to be folded across said insulation with a major surface of said pair of insulation crimping members engaging the insulation of said wire and said members terminating in side by side abutting relation overlying said wire. a t

2. A terminal for attachment to the bare end of an insulated wire, said terminal" comprising: a sheet metal body portion; a pair of Wire-crimping members forme of the sheet metal of said body portion near one end thereof and on opposite sides and bent into a generally U-shaped configuration to be folded over the bare end of said Wire in order to hold the same and to make electrical I contact therewith; said body portion being bent back upon itself and terminating in a right angle bend adjacent said Wire crimping members, and a pair of insulation-gripping members, said insulation gripping members being formed them to fold over the insulation of said who adjacent to the end thereof in side by side relationoverlying said wire, said insulation-gripping members being diagonally inclined to avoid mutual interference when they are folded across said insulation. 7

Rater-erases Cited in the file of this patent UNITED STATESPATENTS 1,845,273 Hosking Feb. 16, 1932, 2,402,122 Bullinger June 18 1946 2,476,738 Klumpp July 19, 1949 r 2,558,052 Klurnpp June 26, 1951 2,630,468 Felts et a1. Mar. 3,1953 2,668,279 Epstein Feb. 2, 1954 2,814,789 Herman etal Nov. 26, 1957 

1. A TERMINAL FOR ATTACHMENT TO ONE END OF AN INSULATED WIRE, SAID TERMINAL COMPRISING: A SHEET METAL BODY PORTION; A PAIR OF WIRE-CRIMPING MEMBERS FORMED OF THE SHEET METAL OF SAID BODY PORTION AT OPPOSITE SIDES OF A CENTRAL REGION THEREOF AND BENT INTO A GENERALLY U-SHAPED CONFIGURATION TO RECEIVE THE BARE END OF SAID WIRE; AND A BIFURCATED END OF SAID BODY PORTION, SAID BIFURCATED END COMPRISING A PAIR OF INSULATION-CRIMPING MEMBERS EXTENDING FROM THE OUTERMOST SIDE REGIONS OF SAID BODY PORTION AND FORMED INTEGRALLY THEREWITH EACH SAID INSULATION CRIMPING MEMBERS BEING BENT SUBSTANTIALLY UPRIGHT FROM THE PLANE OF SAID BODY PORTION AND TWISTED ABOUT THEIR LONGITUDINAL AXES IN OPPOSITE DIRECTIONS SO THAT THE MAJOR SURFACES OF EACH SAID MEMBER ARE SUBSTANTIALLY PARALLEL TO PERMIT THE INSULATION OF SAID WIRE ADJACENT TO SAID BARE END TO BE RECEIVED BETWEEN SAID INSULATION-CRIMPING MEMBERS AND TO PERMIT SAID INSULATION-CRIMPING MEMBERS THEREAFTER TO BE FOLDED ACROSS SAID INSULATION WITH A MAJOR SURFACE OF SAID PAIR OF INSULATION CRIMPING MEMBERS ENGAGING THE INSULATION OF SAID WIRE AND SAID MEMBERS TERMINATING IN SIDE BY SIDE ABUTTING RELATION OVERLYING SAID WIRE. 